It is very much necessary to realize the fact that, the subject is formless(soul) and object(mind or universe) is the form in order to realize non-dualistic or Advaitic truth.

Subject--object relation has to be determined not within waking experience, But between the three states (mind) and its formless witness(soul).

Whatever determined between man and his experience of the world within the waking experience will reveal only the objective knowledge not the knowledge of the subject, which is beyond form, time and space.

"MEHER BABA Said:-A true aspirant is not content with the knowledge of spiritual realities based on hearsay... he insists on the direct knowledge."

Seeker of truth has to verify the fact through soulcentric   reasoning, before accepting anything as truth. Seeker has to accept only un-contradicted truth.

Seeker has to make sure before indulging in pursuit of truth; whether the self is form, or self is formless and have the firm conviction about the true self.

If one finds form is the self, then the religion, yoga, atheism, theories and practices hold good for him, not pursuit of truth.  If one finds the ‘Self’ is formless then he is fit to venture in to path of wisdom or pursuit of truth.

Never indulge in argument with others because pursuit of truth is not pursuit of argument. Truth pursuit is a very personal journey and, it is not for arguing with others and condemning others views and wisdom. But it is for making sure what is truth, and have a firm conviction of truth for himself.

The truth revels only when one knows the real subject, and nature of the object. When one becomes sure mentally the subject is formless object is form, he becomes aware of the fact, that the whole objective experince is mere mirage. And the whole objective experince is created out of the subject which is formless.

Therefore, there is no duality in subjective awareness,because everything is created and witnessed by the subject. Hence there is no second thing other then the formless subject.

There is no proof needed to know about the formless subject. The bulb cannot be powered without the electricity. The same way the dream or waking cannot be powered without the formless subject.

For communication purposes they call and identify with many names and words such as:- spirit, Atman,Consciousness,Awareness, Self, Over self, God, Brahman etc... therefore it not correct to hold a particular word and argue. The words have no meaning in subjective awareness. The words and all the theories hold good in objective awareness(mind or waking experience).

It is very much necessary to realize the fact that,  the subject is formless(soul) and object(mind or universe) is the form in order to realize non-dualistic or Advaitic truth.